I liked your work.

Since the MC has the template of Tobirama it is right to be given his version of flying raijin(the outdated version). But you should also put into consideration that in the MC's timeline Minato exists so both of them could work together and improve the jutsu from the base version. With that not only will the MC have the base version of the flying raijin but also Minato's version of flying raijin

Hestia. Would be nice to see him in a war game